An icebreaker sent to rescue a ship of tourists stuck in Antarctica on Christmas Day is trapped en-route to the liner.
Chinese icebreaker Snow Dragon came within six and a half nautical miles of the Akademic Shokalskiy when it got stuck in ice.
An Australian Maritime Safety Authority official told the Australian Broadcasting Corporation: "It has encountered heavy ice and it's not safe for them to continue to the Russian vessel for their own safety.
"We'll be looking at other options today (Saturday)."
It was stranded 1,500 nautical miles south of Tasmania and two days away from the nearest ship with ice-breaking abilities.
The world's most extreme places
Chinese icebreaker gets stuck on way to rescue ship of 70 tourists
Deep within the Arctic Plateau, a site known as Ridge A, more than 4,000m above sea level, has the coldest average temperatures ever recorded on earth, at -70C. Will Saunders, who led a study team of scientists to find the coldest spot, described it thus: "It's so calm that there's almost no wind or weather there at all."
This is a bit of a contentious one, as several other spots in the Middle East also claim the title, including Jericho, and Sidon in Libya. But archaeologists claim there is evidence of human habitation dating back at least 11,000 years in Damascus. Today, it's a metropolitan area that is home to 2.5 million people.
This spectacular mountain, in Auyuittuq National Park on Baffin Island, Nunavut, has a sheer 4,100ft drop, with an average of 105 degrees. Despite its remote access, it's popular with rock climbers seeking a thrill... but we reckon you'd need to be mad to try it.
Surrounded by canyons and occupying a huge crater bowl 3,600m above sea level on the Altiplano highlands, La Paz leaves you breathless in more ways than one. The city lays claim to the title of highest capital city above sea level (and it boasts the highest airport, too). Second-highest is Quito, Ecuador (2,850m), followed by Bogota in Colombia (2,580m).
Stretching 6,670km (4,160 miles), the Nile flows northwards, beginning in Burundi and stretching through several countries including Uganda, Ethiopia, Sudan, and Egypt, stretching into the Mediterranean Sea.
This small village of around 500 people in the Sakha region of Siberia holds the record for the lowest temperature ever recorded by a permanently inhabited settlement. The lowest temperature recorded here is -71.2C Average temperatures range from -45C in winter to 10C in summer, making it the place with the most significant temperature difference in the world too. It's not an easy place to visit: the nearest city is a three-day drive away...
There's a debate over the hottest place on earth, but with the mercury reaching 70.7C, Iran's Lut Desert has held the highest recorded temperature on the planet since 2005. The 480 sq km area is strewn with dried lava rock, which absorbs the heat of the sun. It's so hot that it's considered abiotic, meaning that no life can be sustained here. Not the best place for a holiday, then...
The highest waterfall in the world, also known as Kerepakupai meru (waterfall of the deepest place) drops nearly a kilometre. 3,212ft (979m) with a clear drop of 2,647ft (807m).
With a peak of 29,028ft (8850m), Everest is five and a half miles above sea level.The world's best known and tallest mountain straddles Tibet and Nepal and is believed to be at least 60 million years old. Thinking of going? The number of people who have attempted to climb Everest is around 4,000. Number of people who have succeeded: Less than 700.
Ok, so at 21,000ft, it's not as tall as Everest. But it's actually closer to the moon and stars than anywhere else on earth, due to the curvature of our planet. This also means its summit is the farthest point on the earth's surface from its centre.